Manufacture of rayon



2,974,005 MANUFACTURE OF RAYON Kurt Heuer, Crehben, Germany, Arnold L. McP-eters, West Asheville, and Albin F. Knight, Asheville, N.C., assignors to American Enka Corporation, Erika, NC, a corporation of Delaware No Drawing. Filed June 2, 1958, Ser. No. 738,950 7 Claims. (Cl. 18--54) The present invention relates to the manufacture of rayon yarn, and more particularly to the production of high tenacity viscose rayon yarn that is characterized by its excellent fatigue resistance and improved strength which makes it especially suitable for use in reinforcing rubber articles such as cord tires and the like.

In an effort to meet the ever increasing competition in this particular field, research efforts are continuing at a high rate among all of the rayon producers with the result that higher quality yarns, particularly with respect to strength and fatigue resistance, are being developed.

One of the most significant developments has been the use of modifiers of the type disclosed in application Serial No. 609,792, filed September 14, 1956 (having common ownership herewith). These compounds are known as Ethoquads and reference is made to the aforesaid application for the chemical and structural formula, but will be spoken of generally in this application as a quaternary derivative of an ethoxylated amine.

Another class of compounds that have been successfully used as modifiers is disclosed in U.S. Patent No. 2,572,217, and reference is made to that patent for the structural and chemical formula of these compounds which are known as Ethomeens, but in this application these compounds will be generally referred to as a long chain aliphatic tertiary amine-ethylene oxide condenate.

It is therefore the object of the present invention to provide an improved process that within certain critical limits will produce an even higher strength yarn than has heretofore been manufactured.

Applicants have now determined that under certain rather critical conditions, a rayon yarn can be produced that is from to 10% higher in yarn and cord strengths than the yarns normally produced with modifiers. This improved process resulted unexpectedly from using an Ethomeen in the acid coagulating bath in very low concentrations while at the same time using the Ethoquad as a modifier in a manner similar to the aforesaid application, provided that certain specific spinning condi tions are observed and followed. It is not known precisely why the use of an Ethomeen in the spinbath in such low concentrations improves the resulting product so significantly, because at such low concentrations it is doubtful whether this chemical will have any strong modifying action on the yarn; but in any event, and for whatever reason, in actual practice the strength of the yarn has been improved while the fatigue resistance is not changed, or may be even improved, or in other words, the flexing life of the yarn is not disturbed by this increase in tensile strength.

The amount of Ethoquad added to the viscose can vary within a limited range but for the best results it has been determined that from 2% to 4% based on oven dry, recoverable cellulose in viscose should be used. Hereinafter, this term is abbreviated to CiV, i.e., cellulose in viscose. The best results are attained if the addition of the Ethoquad to the viscose solution is made in a manner similar to that disclosed in application Serial No.

678,766, filed August 19, 1957 (having common ownership herewith); namely, injecting the Ethoquad into a flowing stream of viscose, thoroughly mixing the modifier with the viscose and then immediately spinning the mixture into an acid coagulating bath to form filamentary arn therefrom.

States Patent 0 Patented Mar. 7, 1961 The effectiveness of an Ethomeen in the spinbath is obtained only within a substantially narrow range of conditions which are as follows:

One of the most essential conditions is that the viscose maturity must be high and the best results are obtained in a range from 17-20 NH Cl number. 3

Some improvement is obtained with as little as 400 p.p.m. of Ethomeen in the spinbath, but in order to obtain the maximum improvement possible, from 800 to 2000 ppm. are required, depending on other spinning conditions.

The temperature of the coagulating bath should be in a range of 47-57" C. for beneficial effects, and consistently the best results are obtained when the temperature of the spinbath is in a range of 48-52 C. The concen ration of zinc sulphate in the spinbath is in a range of 4.5-6.0%.

A spinneret assembly is preferably used of the type shown in U.S. Patent No. 2,834,046, and while the length of the tube is not critical, good results have been obtained when using one from 24 to 36 inches in length depending on the spinning speed.

Specific conditions showing improvements in the yarn and cord strengths are given in the following examples, wherein a control was run with no Ethomeen in the spinbath and compared with the use of 400, 800, and 1800 p.p.m. of Ethomeen in the spinbath.

Example I A viscose was prepared from wood pulp using 7.76% cellulose and 5.9% total alkali. Th viscose was then aged to give a NH Cl number of 20. Immediately before spinning (extruding) the viscose, a water solution was injected containing enough Ethoquad C/25 to provide the viscose with 2.5% CiV. This dilution lowered the viscose composition to 7.5/5.7 and the NH Cl number was lowered to 18. This viscose was spun into a coagulating bath having a composition of 4.8%

H 12% Na SO and 5.0% ZnSO while maintaining the temperature of the bath at approximately 51 C. The viscose was extruded through an 1100 hole spinneret to produce a yarn of 1925 total denier consisting of 1100 filaments. A tube was mounted on the spinneret which was 32 inches in length with a uniform diameter. From the coagulating bath, the yarn was passed over a godet for two 20-inch dips into a second bath having a composition of 4.0% H 80 1.3% Na SO and 0.3% 21180 while being maintained at a temperature of approximately C. During immersion in the second bath, the yarn was stretched 111%. The final speed of the yarn was 55 meters per minute and the yarn was collected in cake form in a centrifugal pot. The cake was washed acid-free, purified, and dried. Finally, it was slashed 11% in an oil emulsion and formed into cords.

A number of samples were spun under exactly the same conditions described above, except that the amount of Ethomeen C/ 25 added to the spinbath was changed. The averages of the resulting singles (yarn) and cord properties are tabulated below.

Ethomeen O/25inSpinbath,p.p.m. I 0 I 400 I 800 Unslashed Singles:

3 Example I] Viscoses were prepared and spun under the same conditions as in Example 1, except that they contained 3.0% Ethoquad C/25 CW, and the spinbath temperature was lowered to 49 C. The samples differed only in the amount of Ethomeen C/ZS" added to the spinbath. The averages of the singles (yarn) and cord properties are tabulated below:

Ethomeen /25 in Spinbath, p.p.m. 0 S00 1800 Unslashed Singles:

Conditioned Strength, g./l00 d 463 464 492 Conditioned Elongation, percent 22,8 22.0 21.8 Slashed Singles:

Ethorneen 0/25 Ethoquad 0/25 It-N derived from coconut fatty acids. :c-l- 15.

it is to be understood that the invention is intended to be limited only to the scope of the appended claims.

What is claimed is:

1. A process for the production of high tenacity, highly fatigue resistant, viscose rayon yarn which comprises incorporating a quaternary derivative of an ethoxylated amine into a viscose solution, extruding the solution through a spinneret into an aqueous sulphuric acid coagulating bath containing zinc sulphate and 800- 2000 p.p.m. of a long chain aliphatic tertiary amineethylene oxide condensate to form a filamentary yarn therefrom and withdrawing the yarn from the bath and aftertreating the same.

2. A process for the production of high tenacity, highly fatigue resistant, viscose rayon yarn which comprises incorporating a quaternary derivative of an ethoxylated amine into a viscose solution, extruding the solution through a spinneret into an aqueous sulphuric acid coagulating bath containing zinc sulphate and at least 400 p.p.m. of a long chain aliphatic tertiary amine-ethylene oxide condensate to form a filamentary yarn therefrom, passing the thus formed yarn to a second hot bath and during passing therethrough stretching the yarn at least 100%.

3. A process for the production of high tenacity, highly fatigue resistant, viscose rayon yarn which comprises incorporating a quaternary derivative of an ethoxylated amine into a viscose solution, extruding the solution through a spinneret into a confined aqueous sulphuric acid coagulating bath containing zinc sulphate and at least 400 p.p.m. of a long chain aliphatic tertiary amine- 6o ethylene oxide condensate to form a filamentary yarn therefrom and withdrawing the yarn from the bath and aftertreating the same.

4. A process for the production of high tenacity, highly fatigue resistant, viscose rayon yarn which comprises in corporating a quaternary derivative of an ethoxylated amine into a viscose solution, extruding the solution through a spinneret into a bath maintained at a temperature of 48-62 C. and containing sulphuric acid, sodium sulphate, zinc sulphate and at least 400 p.p.m. of a long chain aliphatic tertiary amine-ethylene oxide condensate to form a filamentary yarn therefrom and withdrawing the yarn from the bath and aftertreating the same.

'5. A process for the production of high tenacity, highly fatigue resistant, viscose rayon yarn which comprises incorporating a quaternary derivative of an ethoxylated amine into a viscose solution having a maturity in a range of l720 NH Cl number, extruding the solution through a spinneret into an aqueous sulphuric acid coagulating bath containing zinc sulphate and at least 400 p.p.m. of a long chain aliphatic tertiary amineethylene oxide condensate to form a filamentary yarn therefrom and withdrawing the yarn from the bath and aftertreating the same.

6. A process for the production of high tenacity, highly fatigue resistant, viscose rayon yarn which comprises incorporating about 2.5% CiV of a quaternary derivative of an ethoxylated amine into a viscose solution, extruding the solution through a spinneret into an aqueous sulphuric acid coagulating bath containing zinc sulphate and 800-2000 p.p.m. of a long chain aliphatic tertiary amine-ethylene oxide condensate to form a filamentary yarn therefrom and withdrawing the yarn from the bath and aftertreating the same.

7. A process for the production of high tenacity, highly fatigue resistant, viscose rayon yarn which comprises incorporating into a viscose solution a modifier of the following formula:

;CH2CH20);H R--N z- CHz-CH2OMH OH: in which R represents an alkyl radical containing at least six carbon atoms, x+y equal fifteen, and Z is an anion, extruding the solution through a spinneret into an aqueous sulphuric acid coagulating bath containing zinc sulphate and 800 to 2000 p.p.m. of a long chain aliphatic tertiary amine-ethylene oxide condensate to form a filamentary yarn therefrom and withdrawing the yarn from the bath and aftertreating the same.

References Cited in the file of this patent UNITED STATES PATENTS 2,696,423 Dietrich Dec. 7, 1954 2,784,107 Tallis et al. Mar. 5, 1957 2,852,334 Hollihan et a1 Sept. 16, 1958 FOREIGN PATENTS 741,727 Great Britain Dec. 4, 1955 

1. A PROCESS FOR THE PRODUCTION OF HIGH TENACITY, HIGHLY FATIGUE RESISTANT, VISCOSE RAYON YARN WHICH COMPRISES INCORPORATING A QUATERNARY DERIVATIVE OF AN ETHOXYLATED AMINE INTO A VISCOSE SOLUTION, EXTRUDING THE SOLUTION THROUGH A SPINNERET INTO AN AQUEOUS SULPHURIC ACID COAGULATING BATH CONTAINING ZINC SULPHATE AND 8002000 P.P.M. OF A LONG CHAIN ALIPHATIC TERTIARY AMINEETHYLENE OXIDE CONDENSATE TO FORM A FILAMENTARY YARN THEREFROM AND WITHDRAWING THE YARN FROM THE BATH AND AFTERTREATING THE SAME. 